15 Logical Fallacies You Should Know Before Getting Into a Debate

by David Ferrer

A logical fallacy is an error in reasoning common enough to warrant a fancy name. Knowing how to spot and identify fallacies is a priceless skill. It can save you time, money, and personal dignity. Formal fallacies are breakdowns in how you say something, the ideas are ordered wrong somehow. Their form is wrong.

Informal fallacies, like the ones below, have to do with what you are saying (the “content” of an argument). The ideas might be arranged right, but something you said isn’t quite right. The content is wrong. Here’s a list of the 15 informal fallacies you are most likely to encounter in discussion and debate.

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1. Ad Hominem Fallacy

When people think of “arguments,” often their first thought is of shouting matches riddled with personal attacks. Ironically, personal attacks run contrary to rational arguments. In logic and rhetoric, personal attacks are called ad hominems. Ad hominem is Latin for “against the man.” Instead of advancing good sound reasoning, ad hominems replace logical argumentation with attack-language unrelated to the truth of the matter.

More specifically, ad hominems are a fallacy of relevance where someone rejects or criticizes another person’s view on the basis of personal characteristics, background, physical appearance, or other features irrelevant to the argument at issue.

An ad hominem is more than just an insult. It’s an insult used as if it were an argument or evidence in support of a conclusion. Verbally attacking people proves nothing about the truth or falsity of their claims. Ad hominems are common known in politics as “mudslinging.” Instead of addressing the candidate’s stance on the issues, or addressing his or her effectiveness as a statesman or stateswoman, ad hominems focus on personality issues, speech patterns, wardrobe, style, and other things that affect popularity but have no bearing on their competence. In this way, ad hominemscan be unethical, seeking to manipulate voters by appealing to irrelevant foibles and name-calling instead of addressing core issues. In this last election cycle, personal attacks were volleyed freely from all sides of the political aisle, with both Clinton and Trump facing their fair share of ad hominems.

Ad hominem is an insult used as if it were an argument or evidence in support of a conclusion.

Ad hominems often signal the point at which a civil disagreement has descended into a “fight.” Whether it’s siblings, friends, or lovers, most everyone has had a verbal disagreement crumble into a disjointed shouting match of angry insults and accusations aimed at discrediting the other person. When these insults crowd out a substantial argument, they become ad hominems.

See if you can tell which of these is an ad hominem and which is just an insult.

Example 1: “MacDougal roots for a British football team. Clearly he’s unfit to be a police chief in Ireland.”
Example 2: “All people from Crete are liars”

2. Straw Man

It’s much easier to defeat your opponent’s argument when it’s made of straw. The Strawman fallacy is aptly named after a harmless, lifeless, scarecrow. In the straw man fallacy, someone attacks a position the opponent doesn’t really hold. Instead of contending with the actual argument, he or she instead attacks the equivalent of a lifeless bundle of straw, an easily defeated effigy, which the opponent never intended upon defending anyway.

Straw man fallacies are a cheap and easy way to make one’s position look stronger than it is. Using this fallacy, opposing views are characterized as “non-starters,” lifeless, truthless, and wholly unreliable. By comparison, one’s own position will look better for it. You can imagine how straw man fallacies and ad hominems can occur together, demonizing opponents and discrediting their views.

In the straw man fallacy, someone attacks a position the opponent doesn’t really hold.

This fallacy can be unethical if it’s done on purpose, deliberately mischaracterizing the opponent’s position for the sake of deceiving others. But often the straw man fallacy is accidental, because one doesn’t realize he or she is oversimplifying a nuanced position, or misrepresenting a narrow, cautious claim as if it were broad and foolhardy.

See if you can detect how both of the following statements could qualify as a strawman fallacy.

Example 1: “The Senator thinks we can solve all our ecological problems by driving a Prius.”
Example 2: “Quite the contrary, the Senator thinks the environment is such a wreck that no one’s car choice or driving habits would make the slightest difference.”

3. Appeal to Ignorance (argumentum ad ignorantiam)

Any time ignorance is used as a major premise in support of an argument, it’s liable to be a fallacious appeal to ignorance. Naturally, we are all ignorant of many things, but it is cheap and manipulative to allow this unfortunate aspect of the human condition to do most of our heavy lifting in an argument.

Interestingly, this fallacy is often used to bolster multiple contradictory conclusions at once. Consider the following two claims: “No one has ever been able to prove definitively that extra-terrestrials exist, so they must not be real.” “No one has ever been able to prove definitively that extra-terrestrials do not exist, so they must be real.” If the same argument strategy can support mutually exclusive claims, then it’s not a good argument strategy.

Ignorance isn’t proof of anything except that one doesn’t know something. If no one has proven the non-existence of ghosts or flying saucers, that’s hardly proof that those things exist or don’t exist. If we don’t know whether they exist, then we don’t know that they exist or that they don’t exist. Ignorance doesn’t prove any claim to knowledge.

Consider the following examples:

Example 1: “We have no evidence that the Illuminati ever existed. They must have been so clever they destroyed all the evidence.”
Example 2: “I know nothing about Tank Johnson except that he has a criminal record as long as your leg, but I’ll bet he’s really just misunderstood.”

4. False Dilemma/False Dichotomy

This fallacy has a few other names: “black-and-white fallacy,” “either-or fallacy,” “false dichotomy,” and “bifurcation fallacy.” This line of reasoning fails by limiting the options to two when there are in fact more options to choose from. Sometimes the choices are between one thing, the other thing, or both things together (they don’t exclude each other). Sometimes there are a whole range of options, three, four, five, or a hundred and forty-five. However it may happen, the false dichotomy fallacy errs by oversimplifying the range of options.

Dilemma-based arguments are only fallacious when, in fact, there are more than the stated options. It’s not a fallacy however if there really are only two options. For example, “either Led Zeppelin is the greatest band of all time, or they are not.” That’s a true dilemma, since there really are only two options there: A or non-A. It would be fallacious however to say, “there are only two kinds of people in the world, people who love Led Zeppelin, and people who hate music.” Some people are indifferent about that music. Some sort of like it, or sort of dislike it, but don’t have strong feelings either way.

Dilemma-based arguments are only fallacious when, in fact, there are more than the stated options.

The false dilemma fallacy is often a manipulative tool designed to polarize the audience, heroicizing one side and demonizing the other. It’s common in political discourse as a way of strong-arming the public into supporting controversial legislation or policies.

See if you can identify a third option these politicians failed to mention.

Example 1: “Either we go to war or we appear weak.”
Example 2: “Either you love me, or you hate me.”

5. Slippery Slope

You may have used this fallacy on your parents as a teenager: “But, you have to let me go to the party! If I don’t go to the party, I’ll be a loser with no friends. Next thing you know I’ll end up alone and jobless living in your basement when I’m 30!” The slippery slope fallacy works by moving from a seemingly benign premise or starting point and working through a number of small steps to an improbable extreme.

This fallacy is not just a long series of causes. Some causal chains are perfectly reasonable. There could be a complicated series of causes which are all related, and we have good reason for expecting the first cause to generate the last outcome. The slippery slope fallacy, however, suggests that unlikely or ridiculous outcomes are likely when there’s just not enough evidence to think so.

The slippery slope fallacy, however, suggests that unlikely or ridiculous outcomes are likely when there’s just not enough evidence to think so.

Certain ad campaigns from Dodge, Taco Bell, and notably a recent one for Direct TV, commit this fallacy to great comic effect.

It’s hard enough to prove one thing is happening or has happened; it’s even harder to prove a whole series of events will happen. That’s a claim about the future, and we haven’t arrived there yet. We, generally, don’t know the future with that kind of certainty. The slippery slope fallacy slides right over that difficulty by assuming that chain of future events without really proving their likelihood.

Which of these examples is a slippery slope fallacy and which is not?

Example 1: “Your coach’s policy is that no one can be a starter on game day if they miss practice. So, if you miss basketball practice today, you won’t be a starter in Friday’s game. Then you won’t be the first freshman to start on the Varsity basketball team at our school.”
Example 2: “If America doesn’t send weapons to the Syrian rebels, they won’t be able to defend themselves against their warring dictator. They’ll lose their civil war, and that dictator will oppress them, and the Soviets will consequently carve out a sphere of influence that spreads across the entire Middle East.”

6. Circular Argument (petitio principii)

When a person’s argument is just repeating what they already assumed beforehand, it’s not arriving at any new conclusion. We call this a circular argument or circular reasoning. If someone says, “the Bible is true because the Bible says it’s true”—that’s a circular argument. One is assuming that the Bible only speaks truth, and so they trust it to truthfully report that it speaks the truth. Another example of circular reasoning is, “According to my brain, my brain is reliable.” Well, yes, of course we would think our brains are in fact reliable if our brains are the one’s telling us that our brains are reliable.

Circular arguments are also called Petitio principii meaning “Assuming the initial [thing]” (commonly mistranslated as “begging the question”). This fallacy is a kind of presumptuous argument where it only appears to be an argument. It’s really just restating one’s assumptions in a way that looks like an argument. You can recognize a circular argument when the conclusion also appears as one of the premises in the argument.

Another way to explain circular arguments is that they start where they finish, and finish where they started. See if you can identify which of these is a circular argument.

Example 1: “Abstract art isn’t even art. Those pictures and sculptures don’t represent anything, and that’s how you know its not even art.”
Exmaple 2: “We should be tolerant even of people who believe intolerant ideas. Their ideas matter too, and we can still learn different things from them even if their particular intolerant idea is wrong.”

7. Hasty Generalization

Hasty generalizations are general statements without sufficient evidence to support them. They are general claims too hastily made, hence they commit some sort of illicit assumption, stereotyping, unwarranted conclusion, overstatement, or exaggeration.

Normally we generalize without any problem. We make general statements all the time: “I like going to the park,” “Democrats disagree with Republicans,” “It’s faster to drive to work than to walk,” or “Everyone mourned the loss of Harambe, the Gorilla.”

Hasty generalization may be the most common logical fallacy because there’s no single agreed-upon measure for “sufficient” evidence.

Indeed, the above phrase “all the time” is a generalization—we aren’t all the time making these statements. We take breaks to do other things like eat, sleep, and inhale. These general statements aren’t addressing every case every time. They are speaking generally, and, generally speaking, they are true. Sometimes you don’t enjoy going to the park. Sometimes Democrats and Republicans agree. Sometimes driving to work can be slower than walking if the roads are all shut down for a Harambe procession.

Hasty generalization may be the most common logical fallacy because there’s no single agreed-upon measure for “sufficient” evidence. Is one example enough to prove the claim that “Apple computers are the most expensive computer brand?” What about 12 examples? What about if 37 out of 50 apple computers were more expensive than comparable models from other brands?

There’s no set rule for what constitutes “enough” evidence. In this case, it might be possible to find reasonable comparison and prove that claim is true or false. But in other cases, there’s no clear way to support the claim without resorting to guesswork. The means of measuring evidence can change according to the kind of claim you are making, whether it’s in philosophy, or in the sciences, or in a political debate, or in discussing house rules for using the kitchen. A much safer claim is that “Apple computers are more expensive than many other computer brands.”

Meanwhile, we do well to avoid treating general statements like they are anything more than generalizations. Even if it were generally true that women are bad drivers—and I’m not saying they are—there are still plenty of women who are good drivers. And those “cases” just aren’t covered with that general statement even if it were true. In my case, my wife is a better driver than I am. So I do well not to generalize too widely.

A simple way to avoid hasty generalizations is to add qualifiers like “sometimes,” “maybe,” “often,” or “it seems to be the case that . . . “. When we don’t guard against hasty generalization, we risk stereotyping, sexism, racism, or simple incorrectness. But with the right qualifiers, we can often make a hasty generalization into a responsible and credible claim.

Which of the following is a hasty generalization

Example 1: “Some people vote without seriously weighing the merits of the candidate.”
Example 2: “People nowadays only vote with their emotions instead of their brains.”

8. Red Herring (ignoratio elenchi)

A “red herring” is a distraction from the argument typically with some sentiment that seems to be relevant but isn’t really on-topic. Typically, the distraction sounds relevant but isn’t quite on-topic. This tactic is common when someone doesn’t like the current topic and wants to detour into something else instead, something easier or safer to address. Red herrings are typically related to the issue in question but aren’t quite relevant enough to be helpful. Instead of clarifying and focusing they confuse and distract.

Red herrings can be difficult to identify because it’s not always clear how different topics relate.

The phrase “red herring” refers to a kippered herring (salted herring-fish) which was reddish brown in color and quite pungent. According to legend, this aroma was so strong and delectable to dogs that it served as a good training device for testing how well a hunting dog could track a scent without getting distracted. Dogs aren’t generally used for hunting fish so a red herring is a distraction from what he is supposed to be hunting.

Red herrings can be difficult to identify because it’s not always clear how different topics relate. A “side” topic may be used in a relevant way, or in an irrelevant way. In the big meaty disagreements of our day, there are usually a lot of layers involved, with different subtopics weaving into them. We can guard against the red herring fallacy by clarifying how our part of the conversation is relevant to the core topic.

Which of the following examples is a red herring fallacy?

Example 1: “My wife wants to talk about cleaning out the garage, so I asked her what she wants to do with our patio furniture? Now she’s shopping for new patio furniture and not bothering me about the garage.”
Example 2: “My wife wants to talk about cleaning out the garage, so I asked her what she wants to do with the patio furniture? It’s just sitting in the garage taking up space.”

9. Tu Quoque Fallacy

The “tu quoque,” Latin for “you too,” is also called the “appeal to hypocrisy” because it distracts from the argument by pointing out hypocrisy in the opponent. This tactic doesn’t solve the problem, or prove one’s point, because even hypocrites can tell the truth. Focusing on the other person’s hypocrisy is a diversionary tactic. In this way, the tu quoque typically deflects criticism away from one’s self by accusing the other person of the same problem or something comparable. If Jack says, “Maybe I committed a little adultery, but so did you Jason!” Jack is trying to diminish his responsibility or defend his actions by distributing blame to other people. But no one else’s guilt excuses his own guilt. No matter who else is guilty, Jack is still an adulterer.

The tu quoque fallacy is an attempt to divert blame, but it really only distracts from the initial problem. To be clear, however, it isn’t a fallacy to simply point out hypocrisy where it occurs. For example, Jack may say, “yes, I committed adultery. Jill committed adultery. Lots of us did, but I’m still responsible for my mistakes.” In this example, Jack isn’t defending himself or excusing his behavior. He’s admitting his part within a larger problem. The hypocrisy claim becomes a fallacy only when the arguer uses some (apparent) hypocrisy to neutralize criticism and distract from the issue.

Which of the following is a tu quoque fallacy

Example 1: “But, Dad, I know you smoked when you were my age, so how can you tell me not to do it?”
Example 2: “Son, yes, I smoked when I was your age, it was dumb then. And it’s dumb now. That’s why I forbid you to smoke, chew, or vape, or use nicotine gum, or whatever you kids do with tobacco these days.”

10. Causal Fallacy

The Causal Fallacy is any logical breakdown when identifying a cause. You can think of the Causal Fallacy as a parent category for several different fallacies about unproven causes.

One causal fallacy is the False Cause or non causa pro causa (“not the-cause for a cause”) fallacy, which is when you conclude about a cause without enough evidence to do so. Consider, for example, “Since your parents named you ‘Harvest,’ they must be farmers.” It’s possible that the parents are farmers, but that name alone is not enough evidence to draw that conclusion. That name doesn’t tell us much of anything about the parents. This claim commits the False Cause Fallacy.

Another causal fallacy is the Post Hoc fallacy. Post hoc is short for post hoc ergo propter hoc (“after this, therefor because of this”). This fallacy happens when you mistake something for the cause just because it came first. The key words here are “Post” and “propter” meaning “before” and “cause.” Just because this came before that doesn’t mean this caused that. Post doesn’t prove propter. A lot of superstitions are susceptible to this fallacy. For example:

“Yesterday, I walked under a ladder with an open umbrella indoors while spilling salt in front of a black cat. And I forgot to knock on wood with my lucky dice. That must be why I’m having such a bad day today. It’s bad luck.”

Now, it’s theoretically possible that those things cause bad luck. But since those superstitions have no known or demonstrated causal power, and “luck” isn’t exactly the most scientifically reliable category, it’s more reasonable to assume that those events, by themselves, didn’t cause bad luck. Perhaps that person’s “bad luck” is just his own interpretation because he was expecting to have bad luck. He might be having a genuinely bad day, but we cannot assume some non-natural relation between those events caused today to go bad. That’s a Post Hoc fallacy. Now, if you fell off a ladder onto an angry black cat and got tangled in an umbrella, that will guarantee you one bad day.

Another kind of causal fallacy is the correlational fallacy also known as cum hoc ergo property hoc (Lat., “with this therefore because of this”). This fallacy happens when you mistakenly interpret two things found together as being causally related. Two things may correlate without a causal relation, or they may have some third factor causing both of them to occur. Or perhaps both things just, coincidentally, happened together. Correlation doesn’t prove causation.

Consider for example, “Every time Joe goes swimming he is wearing his Speedos. Something about wearing that Speedo must make him want to go swimming.” That statement is a correlational fallacy. Sure it’s theoretically possible that he spontaneously sports his euro-style swim trunks, with no thought of where that may lead, and surprisingly he’s now motivated to dive and swim in cold, wet nature. That’s possible. But it makes more sense that he put on his trunks because he already planned to go swimming.

Which kind of causal fallacy is at work in these examples?

Example 1: “Jimmy isn’t at school today. He must be on a family trip.”
Example 2: “Jimmy has a fever, sinus congestion, a cough, and can’t come to school, so he probably has a test later today.”
Example 3: “Someone really should move this ‘Deer Crossing’ sign. This is a dangerous stretch of highway and the deer really should be crossing somewhere else.”

11. Fallacy of Sunk Costs

Sometimes we invest ourselves so thoroughly in a project that we’re reluctant to ever abandon it, even when it turns out to be fruitless and futile. It’s natural, and usually not a fallacy to want to carry on with something we find important, not least because of all the resources we’ve put into it. However, this kind of thinking becomes a fallacy when we start to think that we should continue with a task or project because of all that we’ve put into it, without considering the future costs we’re likely to incur by doing so. There may be a sense of accomplishment when finishing, and the project might have other values, but it’s not enough to justify the cost invested in it.

We are susceptible to this errant behavior when we crave that sense of completion or a sense of accomplishment

“Sunk cost” is an economic term for any past expenses that can no longer be recovered. For example, after watching the first 6 episodes of Battlestar Galactica, you decide the show isn’t for you. Those six episodes are your “sunk cost.” But, because you’ve already invested roughly 6 hours of your life into it, you rationalize that you might as well finish it. All apologies to Edward James Olmos, but this isn’t “good economics” so to speak. It’s more cost than benefit.

Psychologically, we are susceptible to this errant behavior when we crave that sense of completion or a sense of accomplishment, or we are too comfortable or too familiar with this unwieldy project. Sometimes, we become too emotionally committed to an ‘investment,’ burning money, wasting time, and mismanaging resources to do it.

Consider the following examples. Which of these is a sunk cost fallacy and which is not?

Example 1: “I know this relationship isn’t working anymore and that we’re both miserable. No marriage. No kids. No steady job. But I’ve been with him for 7 years, so I better stay with him.”
Example 2: “I’m halfway done with college. This is so tough, and It’s not nearly as fun as I thought it would be, but I don’t know. I guess I’ll finish it and get my degree.”

12. Appeal to Authority (argumentum ad verecundiam)

This fallacy happens when we misuse an authority. This misuse of authority can occur in a number of ways. We can cite only authorities—steering conveniently away from other testable and concrete evidence as if expert opinion is always correct. Or we can cite irrelevant authorities, poor authorities, or false authorities.

Like many of the other fallacies in this list, the argumentum ad verecundiam (“argument from respect”) can be hard to spot. It’s tough to see, sometimes, because its normally a good responsible move to cite relevant authorities supporting your claim. It can’t hurt. But if all you have are authorities, and everyone just has to “take their word for it” without any other evidence to show that those authorities are correct, well then you have a problem.

Often this fallacy refers to irrelevant authorities—like citing a foot doctor when trying to prove something about Psychiatry; his or her expertise is in an irrelevant field. When citing authorities to make your case, you need to cite relevant authorities, but you also need to represent them correctly, and make sure their authority is legitimate.

Suppose someone says, “I buy Fruit of the Loom™ underwear because Michael Jordan says it’s the best.” But Michael Jordan isn’t a relevant authority when it comes to underwear. This is a fallacy of irrelevant authority.

Now consider this logical leap: “4 out of 5 dentists agree that brushing your teeth makes your life meaningful.” Dentists generally have expert knowledge about dental hygiene, but they aren’t qualified to draw far-reaching conclusions about its meaningfulness. This is a fallacy of misused authority. For all we know, their beliefs about the “meaning of life” are just opinions, not expert advice.

Or take the assumption that “I’m the most handsome man in the world because my Mommy says so.” Now, while I might be stunningly handsome, my Mom’s opinion doesn’t prove it. She’s biased. She’s practically required to tell me I’m handsome because it’s her job as a mother to see the best in me and to encourage me to be the best I can be. She’s also liable to see me through “rose-colored glasses.” And, in this case, she’s not an expert in fashion, modeling, or anything dealing in refined judgments of human beauty. She’s in no position to judge whether I’m the most handsome man in the world. Her authority there is illusory. (Sorry Mom.)

There’s another problem with relying too heavily on authorities. Even the authorities can be wrong sometimes. The science experts in the 16th century thought the earth was the center of the solar system (Geocentrism). Turns out they were wrong. The leading scientists, in the 19th century, thought the universe as we know it always existed (Steady State theory). They too were wrong. For these reasons, it’s a good general rule to treat authorities as helpful guides with suggestive evidence. But even authorities deserve a fair share of skepticism since they can make mistakes, overstep their expertise, and otherwise mislead you.

Consider the following examples. How do these statements mishandle authorities?

Example 1: “Because Martin Sheen played the president on Television, he’d probably make a great president in real life.”
Example 2: “One day robots will enslave us all. It’s true. My computer science teacher says so.”
Example 3: “This internet news site said that the candidate punches babies. We know that’s true because it’s on the internet.”

13. Equivocation (ambiguity)

Equivocation happens when a word, phrase, or sentence is used deliberately to confuse, deceive, or mislead by sounding like it’s saying one thing but actually saying something else. Equivocation comes from the roots “equal” and “voice” and refers to two-voices; a single word can “say” two different things. Another word for this is ambiguity.

When it’s poetic or comical, we call it a “play on words.” But when it’s done in a political speech, an ethics debate, or in an economics report, for example, and it’s done to make the audience think you’re saying something you’re not, that’s when it becomes a fallacy. Sometimes, this is not a “fallacy” per se, but just a miscommunication. The equivocation fallacy, however, has a tone of deception instead of just a simple misunderstanding. Often this deception shows up in the form of euphemisms, replacing unpleasant words with “nicer” terminology. For example, a euphemism might be replacing “lying” with the phrase “creative license,” or replacing my “criminal background” with my “youthful indiscretions,” or replacing “fired from my job” with “early retirement.” A romantically involved couple might discuss their relationship to others as “just friends” so they appear like they have no other romantic relations. When these replacement words are used to mislead people they become an equivocation fallacy.

Which of these examples is an equivocation fallacy?

Example 1: “His political party wants to spend your precious tax dollars on big government. But my political party is planning strategic federal investment in critical programs.”
Example 2: “I don’t understand why you’re saying I broke a promise. I said I’d never speak again to my ex-girlfriend. And I didn’t. I just sent her some pictures and text messages.”

14. Appeal to Pity (argumentum ad misericordiam)

Argumentum ad misericordiam is Latin for “argument to compassion”. Like the ad hominem fallacy above, it is a fallacy of relevance. Personal attacks, and emotional appeals, aren’t strictly relevant to whether something is true or false. In this case, the fallacy appeals to the compassion and emotional sensitivity of others when these factors are not strictly relevant to the argument. Appeals to pity often appear as emotional manipulation. For example,

“How can you eat that innocent little carrot? He was plucked from his home in the ground at a young age, and violently skinned, chemically treated, and packaged, and shipped to your local grocer and now you are going to eat him into oblivion when he did nothing to you. You really should reconsider what you put into your body.”

Obviously, this characterization of carrot-eating is plying the emotions by personifying a baby carrot like it’s a conscious animal. So, by the time the conclusion appears, it’s not well-supported. If you are to be logically persuaded to agree that “you should reconsider what you put into your body,” then it would have been better evidence to hear about unethical farming practices or unfair trading practices such as slave labor, toxic runoffs from fields, and so on.

Truth and falsity aren’t emotional categories, they are factual categories. They deal in what is and is not, regardless of how one feels about the matter. Another way to say it is that this fallacy happens when we mistake feelings for facts. Our feelings aren’t disciplined truth-detectors unless we’ve trained them that way. So, as a general rule, it’s problematic to treat emotions as if they were (by themselves) infallible proof that something is true or false. Children may be scared of the dark for fear there are monsters under their bed, but that’s hardly proof of monsters.

Truth and falsity aren’t emotional categories, they are factual categories.

To be fair, emotions can sometimes be relevant. Often, the emotional aspect is a key insight into whether something is morally repugnant or praiseworthy, or whether a governmental policy will be winsome or repulsive. People’s feelings about something can be critically important data when planning a campaign, advertising a product, or rallying a group together for a charitable cause. But it becomes a fallacious appeal to pity when the emotions are used in substitution for facts or as a distraction from the facts of the matter.

It’s not a fallacy for jewelry and car companies to appeal to your emotions to persuade you into purchasing their product. That’s an action, not a claim, so it’s can’t be true or false. It would however be a fallacy if they used emotional appeals to prove that you need this car, or that this diamond bracelet will reclaim your youth, beauty, and social status from the cold clammy clutches of Father Time. The fact of the matter is, you probably don’t need those things, and they won’t rescue your fleeting youth.

Which of these is a fallacious appeal to emotion, and which one is not?

Example 1: “The government needs to hear our cry because we are scared. We are scared that this candidate will not respect us or protect us. We are scared about our future. There’s no hope for people like us with these candidates in office.”
Example 2: “These candidates stated that they would close down the education department and that has many teachers worried about their jobs in 2017.”

15. Bandwagon Fallacy

The bandwagon fallacy assumes something is true (or right, or good) because other people agree with it. A couple different fallacies can be included under this label, since they are often indistinguishable in practice. The ad populum fallacy (Lat., “to the populous/popularity”) is when something is accepted because it’s popular. The concensus gentium (Lat., “consensus of the people”) is when something is accepted because the relevant authorities or people all agree on it. And the status appeal fallacy is when something is considered true, right, or good because it has the reputation of lending status, making you look “popular,” “important,” or “successful.”

For our purposes, we’ll treat all of these fallacies together as the Bandwagon Fallacy. According to legend, politicians would parade through the streets of their district trying to draw a crowd and gain attention so people would vote for them. And whoever supported that candidate was invited to literally jump on board the bandwagon. Hence the nickname “Bandwagon Fallacy.”

This tactic is common among advertisers. “If you want to be like Mike (Jordan), you’d better eat your Wheaties.” “Drink Gatorade because that’s what all the professional athletes do to stay hydrated.” “McDonald’s has served over 99 billion, so you should let them serve you too.” The form of this argument often looks like this: “Many people do or think X, so you ought to do or think X too.”

One problem with this kind of reasoning is that the broad acceptance of some claim or action is not always a good indication that the acceptance is justified. People can be mistaken, confused, deceived, or even willfully irrational. And when people act together, sometimes they become even more foolish—i.e., “mob mentality.” People can be quite gullible, and this fact doesn’t suddenly change when applied to large groups. Which of these is a bandwagon fallacy?

Example 1: “Almost everyone at my school will be at the party Friday night. It must be a popular thing to do.”
Example 2: “Almost everyone at my school will be at the party Friday night. It must be the right thing to do.”

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We hope this little primer on logical fallacies helps you to navigate future disputes with friends, family and unhinged online acquaintances without descending into vitriol or childish name-calling. Or at least if it does descend into vitriol and childish name-calling, you’ll be in a great position to rhetorically trounce your opponent with sound reasoning and airtight logic.

Did we miss any commonplace logical fallacies? Let us know in the comments section below!

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Thanks for your question Don. The 15 Logical fallacies is not an exhaustive list, so that’s why it doesn’t include the fallacy of assertion (i.e., presuming something true just because it’s been asserted as such), or Big Lie Technique (a propaganda strategy of repeating a known lie till people believe it). I had to look up “Big Lie Technique” and found it as #26 at http://utminers.utep.edu/omwilliamson/ENGL1311/fallacies.htm. I hope that helps.

I think what he said about the bandwagon fallacy is true as he stated in the video “you are somebody if you go to a game” because most people who go and watch games do not go because of the game, they either go for fun or for people to see they actually went for the game, for people to think they can afford the ticket or call them rich kids.

Fair point. Strictly speaking, informal fallacies don’t prove things “false” or “true.” So the claim about “going to the game” may be true, but the mere fact that it’s a popular view doesn’t make it true. It could be that it’s a popular view and still false. The only thing that makes a view true is whether it corresponds with its reference point. Informal fallacies, like the bandwagon fallacy, are about credibility not veracity. They just point out where someone’s statement or line of argument is somehow unworthy of belief. Is it a credible claim? is it worthy of belief in light of the evidence and argument they’ve offered? If it’s not credible, then we should try to identify what formal fallacy or informal fallacy compromised the credibility of that claim.

I personally have a problem with the appeal to own authority fallacy and I am still seeking a way to expose it as such,because,their line of reasoning is that since they are more powerful,they are right,the trouble is,since they are more powerful they can enforce this faulty logic without much resistance,they assume that since they are more powerful they are more knowledgeable because the few who dare correct them or even ask why are immediately punished to the full,and are only greeted with,” Because I am the authority,therefore I am right and you do not need to see my logic”(or lack thereof,it’s like the scene in star wars where Obi wan but obi wan goes “this is not the logic (or lack thereof once more I must say.) you’re looking for.”

thank you for your input. I agree, the appeal to authority can be tricky. Perhaps it’s because there is a responsible and legitimate role for authority-appeals. It can be frustrating when someone misuses authority, for example, a teacher who turns his lecturn into a bully pulpit and then appeals to his own authority as if that somehow makes his opinions true. If your teacher is speaking within his field of expertise, then that authority appeal can lend legitimate credibility to his claims. However, if he is speaking outside of his field of experience/study, then it’s a fallacious appeal to authority. And even if he is speaking within his field, he can still be wrong. Adding credibility doesn’t make a lie any truer. Even the experts can be mistaken. The only thing that makes a claim true is whether, in reality, it corresponds to its reference point.

I published a book, based on research, about how Millennials and Gen X workers interact in the workplace. While engaged in a debate about the average Millennial expectations in the workplace, I was called out for a logical fallacy for referring to my own research. What are your thoughts on this? Is this Indeed an appeal to authority or is legitimate logical reasoning? I never said, “I’m right because I have experience with this.” I provided examples from research in the book.

I’ve had at times several of these in one argument, where I’ve asked a clear technical question, and the response is a series of fallacies.

Along the lines of “please provide the required technical specification for a 45m long fire hose reel, as the design codes don’t specify the requirements and only allow for 30m length”.

The answers have at times included:
1. Everyone has agreed that a 45 m hose reel is acceptable [followed by a list of attendees at a meeting, where yours truly disagreed with conclusions] (Bandwagon)
2. Local regulations ask for it to be 45m (Appeal to Authority)
3. We’ve already done all the drawings based on 45m and would have to draw again [when redrawing everything anyway] (Sunk costs)
4. The 45m reel isn’t needed as we have sprinklers, so why change anything [So why provide it in the first place?] (Equivocation)
5. We can’t change everything even if we think its wrong, we have to assess what we change carefully [If we allow this you’ll want to change other things] (slippery slope)
6. Your an Architect, you don’t have the professional knowledge to comment on this [Err, yes I do] (Red herring and Ad Hominem)

I’m yet to get a proper specification, or design for that matter, that is code compliant.

Not a fallacy, more a strategy :

*Ignore someone and the problem they raise long enough, and they’ll either go away, or it will become too late to do anything by when you do acknowledge the problem exists, and you can then claim the impact of change is too high to be considered.

Hillary has been in politics for a looooong time. People judge her based on her ACTIONS. She didn’t get those names by mistake. There is actual proof to support calling her Killary Clinton among others. Benghazi for one. Now, Trump just got into politics, so he has no record to be judged upon.

John,
Thanks so much for your comment, and for demonstrating at least three logical fallacies in your own response. At first glance, I see a Straw man argument, an appeal to ignorance and a false dichotomy. Shows you’re paying attention. Thanks again for reaching out!

The differential distillation comparison error. The two factors have come from populations which have had varied paths to inclusion. Example stock picking success. If 20 men are in a firm with 10 women and you find out the average women is better at picking stocks this should not be a surprise because the 10 women come from a somewhat equal population of men/women but are distilled 1 to 2 making the samples unrepresentative. Many studies I have read have variations within the difference of median and average, but claim significance.

Is the journalist who wrote an editorial containing the following quotation below pointing to a logical fallacy? The editorial supports the Supreme Court ruling that the flag was not an exception to the “joust of principles” protected by the First Amendment and, therefore, burning the flag is a type of free expression protected by that amendment. The editorial says, “The controversy will rage precisely because burning the flag is such a powerful form of communication. Were it not, who would care? Thus were we to embrace a prohibition on such communication, we would be saying that the First Amendment protects expression only when no one is offended. That would mean that this aspect of the First Amendment would be of virtually no consequence. It would protect a person only when no protection was needed.”

It seems that one who ascribes to a principle that protects a person only when no protection is needed is the victim of a logical fallacy, but this kind of thing does not appear in your list, nor am I sure that it’s actual LOGIC that’s missing from that person’s reasoning.

Can you help me identify what’s going on here? What is a person who offers forks only when everyone has finished dinner doing? That is, what is providing something that does no good an example of?

I am trying to figure out the name for the argument that people make when someone cares about a particular issue, such as gun control, and another person says, for instance, you want to talk about the need for gun control while there are millions of people suffering from opioid addiction. In other words, as if caring about one issue means you don’t care about another issue, or many other issues. Thanks!

Alisha,
I believe that would be considered “false equivalence.” From Wiki, a false equivalence is “a logical fallacy in which two opposing arguments appear to be logically equivalent when in fact they are not. This fallacy is categorized as a fallacy of inconsistency.”

Alisha,
To me it sounds like you might be describing a red herring fallacy. Red herring arguments are fallacies of relevance that take are intended to take people off topic. From your example, the shred of apparent relevance regarding caring for people, but that is not the topic of the argument.

I think the Red Herring fallacy may be the closest. But Just to throw in another variant in the mix, see this:

❝Whataboutism (also known as whataboutery) is a variant of the tu quoque logical fallacy that attempts to discredit an opponent’s position by charging them with hypocrisy without directly refuting or disproving their argument, which is particularly associated with Soviet and Russian propaganda. When criticisms were leveled at the Soviet Union, the Soviet response would be “What about…” followed by an event in the Western world.❞

Thanks for writing this article! I’m studying to be a teacher and plan to educate my students about these logical fallacies, starting in elementary school.

I do have a question, though. What type of fallacy is it when you assume that because someone supports one course of action (i.e. gun control) that they are automatically against other options (i.e. mental health programs or security systems)? I’ve seen this one a lot lately.

False dilemma/false dichotomy would fit. Anytime there are in fact more options/sides/positions to consider, but it’s presented as if there are only two, it’s a false dichotomy. It’s a very common fallacy. It’s also far too common that a person will present their unfavorable choice in a poor manner, compounding fallacies, like making option A a straw man.

It seems to me that not long ago I read about a fallacy wherein a person tends to believe that they themselves are able to consider a subject critically/objectively, but that their opponent will just believe whatever is shown. An example might be if I were to say, “If Fox News says that Hilary Clinton is a member of Isis, they will believe it.” or conversely, if a Fox News fan said, “If CNN said ‘Donald Trump reports directly to Vladimir Putin,’ they would believe it.” The idea that I can view a story and recognize its truth/merit (or lack), but that others, especially those who would disagree, just believe what they are told. Is there a name for this fallacy?

One argues that we need more gun control because it will reduce the amount of people killed.
Counterargument is: there are things that kill more people, such as cars, so we should focus on regulating cars instead of guns
The point of the debate was gun control, not a discussion on the best way to save lives. I believe the counterargument is a fallacy because it negates the actual topic being debated. Am I correct, and if so, what sort of fallacy would that fall under?

Mike,
Thanks for reading. This is a perfect demonstration of “false dichotomy.” The counterargument seems to suggest that we must either decide between auto safety or gun control when in fact neither is a mutually exclusive priority. It presents a false choice between two options, each of which can, in actuality, be pursued in its own right.

I’m trying to identify the fallacy / tactic that goes something like this:

Person 1: I think you have a problem with alcohol
Person 2: That’s absurd, I definitely do not have a problem with alcohol
Person 1: That’s exactly what someone who has a problem with alcohol would say

This tactic essentially makes it impossible for person 2 to refute the claim being leveled against them because the denial itself is “proof” that the initial claim is accurate (or implies that at the very least that their denial is highly suspect because it is the expected response for nearly anyone about whom the claim is accurate.)

It also necessarily ignores that this denial would be completely accurate and expected for anyone about whom the claim was totally untrue.

Or put another way, there are two kinds of people who would deny being an alcoholic: people who are alcoholics and people are not alcoholics

I’m seeing this tactic/fallacy used more and more frequently in more subtle ways, particularly in our political debates. It’s employed in a way that’s similar to false equivalence but has a different twist:

Person 1: The problem is that we don’t listen to each other anymore and just go straight to “you’re an idiot” or try to blame the “other side” side for everything
Person 2: Yeah, but the other side is actually to blame for a lot more things, disproportionately
Person 1: See, this is exactly the problem. You’re proving my point.

This doesn’t allow for the fact that one side could very easily be more wrong or worse or more responsible than the other and tries to shift blame equally while criticizing the person making the (possibly accurate) observation and including them as part of the problem. Or to put it more starkly:

Person 1: I feel like we all just need to listen to each other more, the oppressed need to do a better job of listening to the oppressor and vice versa.
Person 2: But the oppressor is the problem here. The oppressed aren’t to blame.
Person 1: See, that’s exactly what I’m talking about. You just proved my point.